JP2000239690A - Water-based metal surface treating composition for forming lubricating film excellent in scratch resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based metal surface treating composition for forming a lubricating resin film excellent in corrosion resistance, film adhesion, and scratch resistance. SOLUTION: This composition comprises (a) a water-based urethane resin which is a water-based urethane resin having a bisphenol skeletons and carboxyl groups in the resin skeleton and has an average molecular weight of 3,000 or above and in which the content of nitrogen taking part in the reaction of an isocyanate during the synthesis of the resin is in the range of 2-13 wt.%, and the ratio, nitrogen atoms of urea bonds/nitrogen atoms taking part in the reaction of the isocyanate, i.e., the ratio of the nitrogen atoms taking part in urea bonds to the nitrogen atoms taking part in the reaction of the isocyanate during the synthesis of the resin, is in the range of 10/100 to 90/100, (b) a curing agent, (c) silica, and (d) a polyolefin wax, and wherein the weight of the solids of components (a) and (b) is 50-95% based on the total weight of solids (e), the equivalent ratio of the functional groups of component (b) to the equivalents of the carboxyl contained in the skeleton of component (a) is 0.10-1.00, the amount of the solids of component (c) is 3-40 wt.% based on the solids of component (e), and the amount of the solids of component (d) is 2-30% based on the total weight (e) of solids.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous metal surface treatment composition for forming a lubricating film having excellent scratch resistance.

[0002]

2. Description of the Related Art Conventionally, cold-rolled steel sheets or galvanized steel sheets are frequently used by processing and assembly manufacturers of home appliances, automobiles, building materials and the like. , Painting assembly is being performed. However, some materials are insufficiently molded, and a lubricant represented by press oil is applied in the molding process to achieve the desired moldability. However, when the paint assembly is performed thereafter, a lubricant that can remove the applied lubricant in the degreasing step must be used.

[0003] For this reason, in recent years, the number of processes has been reduced, costs have been reduced,
For the purpose of improving the working environment, steel sheets have been manufactured in which a wax-based lubricant is previously applied to the plate surface without using press oil. However, the wax-based lubricant needs to be removed in the subsequent degreasing step, and although the press environment is improved as compared with the case of the press oil, it cannot be said to be good. For this reason, functional surface-treated steel sheets having more appropriate lubricating surfaces have been developed. This steel sheet is coated with a thin film of a composition mainly composed of an organic resin with good lubricity, and can be formed without the need to apply a lubricant such as press oil, and can be degreased thereafter. This is a surface-treated steel sheet that does not require any process or coating base treatment.

Conventional techniques relating to the functional surface-treated steel sheet include (1) JP-A-61-231177, JP-A-61-279687, and JP-A-62-33781.
(2) JP-A No. 62-289274, (3) JP-A No. 60-289274
No. -103185, (4) Tokuhei 6-92567,
(5) JP-B-6-104799, (6) JP-A-6-2
There is a technology disclosed in Japanese Patent No. 92859,
This is outlined below.

[0005] The technology disclosed in each of the publications (1) is capable of copolymerizing a monomer represented by the general formula CH ₂ = CR ₁ -COOR ₂ with an α, β unsaturated carboxylic acid monomer and these monomers. A film containing a silane coupling agent and / or a titanium coupling agent, a chromate, a silica sol, a fine colored pigment and a solid lubricant is formed on the surface of a steel sheet in an emulsion polymer composed of various monomers. The present invention relates to a surface-treated steel sheet characterized by the following. The film obtained in this way is effective for relatively mild processing such as bending and overhanging, but the sliding surface is not suitable for strong processing such as drawing or ironing as represented by press forming. When the temperature rises to 100 ° C. or higher, the resin film layer is easily peeled off, and the resin peeling powder adheres to the surface of the mold and the press-formed product, which causes a problem that the appearance after processing is impaired. The gazette disclosed in (2) is characterized in that a coating layer mainly composed of a composite material or a mixed material of a urethane resin and silicon dioxide is provided on a galvanized steel sheet. Here, the urethane-based resin refers to a mixture of a urethane resin and another resin (epoxy, acrylic, phenol, or the like). The film thus obtained is effective for low-speed sliding molding (10 mm / sec or less), but is effective for high-speed sliding molding (500 mm / sec) such as press molding.
Before and after), the target high lubricity could not be achieved because of the peeling of the film. The gazette disclosed in (3) is to provide a specific chromate layer on zinc or galvanized steel sheet,
Furthermore, a two-layered composite film comprising a composite aluminum phosphate, a chromate-based rust-preventive pigment, polyolefin wax, molybdenum disulfide, a silicone resin, and a terminally aminated urethane-modified epoxy resin is formed thereon. It relates to a chromate treated steel sheet. Since this film uses a self-crosslinking type terminally aminated urethane-modified epoxy resin, relatively stable performance can be obtained without a crosslinking agent, but the target performance level was not reached. The official gazette disclosed in (4) discloses a resin composition comprising a resin selected from an epoxy resin, a polyester resin, and an acrylic resin and an amino resin or a polyisocyanate as a curing agent component, in which a conductive material, a chromium compound, and a lubricating material are added. It is characterized by being blended. In the coating obtained in this way, the coating itself did not have sufficient abrasion resistance, so that the intended scratch resistance during high-speed sliding could not be achieved. The gazette disclosed in (5) discloses that a polyester resin and a crosslinking agent have an average molecular weight of 2
It is characterized in that a film containing 000 to 8000 polyethylene wax is formed on the surface of the steel sheet. The film obtained in this way could not achieve the target performance level (corrosion resistance, coating adhesion) because the film itself was not sufficiently hydrolyzable.
The gazette disclosed in (6) discloses that a film containing a urethane-based resin having an active hydrogen in a molecule, a cold-crosslinkable epoxy-based resin, a spherical polyethylene wax and a chain colloidal silica is formed on a steel sheet surface. It is a feature. The urethane resin used for this film is not specified, and many films whose performance cannot reach the target performance level have been observed. Therefore, at present, a water-based coating composition having good scratch resistance during strong working, and excellent corrosion resistance and coating adhesion has not been obtained.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art.
An object of the present invention is to provide a water-based lubricating coating composition for a highly functional surface-treated plate having scratch resistance during strong working, and excellent in corrosion resistance and coating adhesion.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, they have found that they contain an aqueous urethane resin having a specific structure, a curing agent, silica and a polyolefin wax. The present inventors have found that it is preferable to use an aqueous metal surface treatment composition, and have completed the present invention. That is, (a) the resin skeleton contains a bisphenol skeleton and a carboxyl group and has an average molecular weight of 300
0 or more aqueous urethane resins, wherein the nitrogen content involved in the reaction of isocyanate during the synthesis of the resin is in the range of 2 to 13% by weight, and the urea bond in the nitrogen element involved in the reaction of the isocyanate during the synthesis of the resin. An aqueous urethane resin in which the nitrogen involved in the urea bond nitrogen / isocyanate reaction, which is the ratio of the nitrogen element according to the present invention, is in the range of 10/100 to 90/100, (b) a curing agent, and (c) silica;
(D) a polyolefin wax, and (a) + (b) solid content weight% of the total solid content weight (e)
Is 50 to 95%, and the equivalent ratio of the functional group in (b) to the equivalent of the carboxyl group contained in the skeleton of (a) is 0.1%.
0 to 1.00, 3 to 40% by weight of the solid content of (c) with respect to (e), and 2 to 30% by weight of the solid content of (d) with respect to (e). Provided is an aqueous metal surface treatment composition for forming a lubricating film having excellent scratch resistance. The nitrogen content of the aqueous urethane resin of the present invention is more preferably in the range of 5 to 10% by weight. In the surface treatment composition of the present invention, the curing agent preferably has at least one functional group selected from an epoxy group and an isocyanate group. In the surface treatment composition of the present invention, the amount of the carboxyl group in the aqueous urethane resin is preferably 10 to 50 in terms of an acid value per solid content of the resin. In the surface treatment composition of the present invention, the polyolefin wax preferably has a saponification value of 30 or less or 0 and has a branched structure. In the surface treatment composition of the present invention, the polyolefin wax preferably has an average particle size of 0.1 to 7.0 μm.

Hereinafter, the contents of the present invention will be described in detail. A first feature of the present invention resides in that an appropriate type of resin is blended at a constant weight ratio as a base resin. As the resin, it is necessary to use a component having a well-balanced adhesion, elongation, shear strength, corrosion resistance, abrasion resistance, and chemical resistance. In order to satisfy these performances, it is preferable to use the resin of the present invention. The present inventors have already achieved to obtain strong workability and corrosion resistance by blending a urethane resin and an epoxy resin and blending a specific wax, but as a result of further intensive research, the structure of the urethane resin was It has been found that by specifying, particularly excellent performance is exhibited.

In order to achieve high workability and high corrosion resistance,
It is important that the strength and elongation of the coating film be balanced. By using a urethane resin having an average molecular weight of 3000 or more and a curing agent, it is easier to control basic physical properties than a film formed by crosslinking resins having low molecular weights,
Further, it has been found that even with a thin film having a dry film weight of 0.3 to 5.0 g / m ² , uniform physical properties can be easily obtained. In addition, the low molecular weight urethane resin refers to a resin containing various isocyanate-based curing agents.

The bisphenol skeleton serving as the skeleton of the aqueous urethane resin used in the surface treatment composition of the present invention includes:
Methylene bisphenol, ethylidene bisphenol,
Examples include butylidene bisphenol, isopropylidene bisphenol, and their alkylene oxide (propylene oxide, butylene oxide, etc.) adducts, or epoxy-modified polyols obtained by reacting an epoxy resin having a bisphenol skeleton with an organic amine. By incorporating this skeleton into the resin,
Corrosion resistance, adhesion, etc. are greatly improved. The number of moles of the alkylene oxide added is not particularly limited, but is preferably 0 or 10 or less. When it exceeds 10, the molecular weight of the glycol becomes too large, so that the hydrophilicity of the obtained resin film becomes strong, and the corrosion resistance and the coating adhesion are reduced. Examples of the organic amine include dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diamylamine, dimethanolamine, diethanolamine, and methylethanolamine.

In the aqueous urethane resin used in the present invention, a polyester polyol compound and a polyether polyol may be used as a skeleton in addition to a polyol having a bisphenol skeleton. As the polyester polyol compound, for example, ethylene glycol,
Diethylene glycol, triethylene glycol, 1,
Low molecular weight polyols such as 2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, hexamethylene glycol, trimethylolpropane, and glycerin A hydroxyl group at the end obtained by the reaction with succinic acid, glutamic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, endmethylenetetrahydrophthalic acid, hexahydrophthalic acid, etc. And a polyester compound having the formula: Examples of the polyether compound include ethylene glycol, diethylene glycol, triethylene glycol,
-Propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, hexamethylene glycol, hydrogenated pisphenol A, trimethylolpropane, glycerin, etc. An ethylene oxide and / or propylene oxide high adduct of a low molecular weight polyol,
Polyethylene glycol, polypropylene glycol,
Polyether polyols such as polyethylene / propylene glycol, polycaprolactone polyols, polyolefin polyols, polybutadiene polyols and the like can be mentioned.

The aqueous urethane resin used in the present invention is characterized by containing a carboxyl group in the skeleton.
Other urethane resins that do not contain a hydrophilic group such as a carboxyl group cannot be water-based because of insufficient hydrophilicity. A method of introducing a sulfonic acid salt into a side chain is known as an aqueous method without introducing a carboxyl group, but in this method, the water resistance of a film obtained because the hydrophilicity of the sulfonic acid salt is too strong. descend. Further, a method of forcibly converting to an aqueous system by using an emulsifier is also known. However, since the active agent used generally has a strong hydrophilicity, the water resistance of the obtained film is reduced. For this reason, a method in which a carboxyl group is contained in the resin skeleton, and this is neutralized with an alkali such as ammonia or triethylamine and self-emulsified is preferred. It is appropriate that the amount of the carboxyl group is in the range of 10 to 50 in terms of an acid value per solid content of the urethane resin.
When the acid value is less than 10, the adhesiveness is insufficient and the workability and the corrosion resistance are poor. On the other hand, when the acid value exceeds 50, the corrosion resistance is reduced due to poor water resistance and alkali resistance. In addition,
The method for introducing a carboxyl group into the aqueous urethane resin is not particularly limited, but generally, dimethylolalkanoic acid (for example, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2- Dimethylol valeric acid) is often used.

The aqueous urethane resin used in the present invention comprises:
It is characterized in that the nitrogen content involved in the reaction of isocyanate during the synthesis of the resin is in the range of 2 to 13% by weight. More preferably, it is in the range of 5 to 10% by weight. When the nitrogen content is less than 2% by weight, the concentration of the bond relating to the reaction with the isocyanate in the aqueous urethane resin decreases, so that the excellent wear resistance unique to the urethane resin decreases. On the other hand, if the nitrogen content exceeds 13% by weight, the concentration of the bond relating to the reaction with the isocyanate in the aqueous urethane resin becomes too high, and the resulting film becomes brittle, and follows the elongation due to plastic deformation of the material. It will not be able to be removed, and the film will be damaged, and the corrosion resistance and paint adhesion will decrease.

Another major feature of the water-based urethane resin used in the present invention is that the ratio of nitrogen in the urea bond, which is the ratio of the nitrogen element in the nitrogen element involved in the reaction of the isocyanate in the synthesis of the resin, is determined. / Nitrogen involved in isocyanate reaction is 10/10/90 to 90/10
0. More preferably 40
/ 100 to 80/100. The ratio is 10 /
When it is less than 100, the tensile strength at the time of high-speed sliding, that is, at a high temperature is insufficient, so that the film is peeled off and the scratch resistance is reduced. On the other hand, if the ratio exceeds 90/100, the film is too hard to follow the elongation due to the plastic deformation of the material, and the film is damaged, and the corrosion resistance and the paint adhesion deteriorate. As a method of introducing a urea bond into the resin skeleton, a method of reacting an isocyanate group and an amino group during the synthesis of a urethane prepolymer, a method of reacting a urethane prepolymer having a terminal isocyanate group with water, and the like are known. However, the present invention is not particularly limited. Here, as the compound having an amino group used, for example, ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diaminodiphenylmethane,
Examples include diaminocyclohexylmethane, pyrerazine, 2-methylpyrazine, isophoronediamine, succinic dihydrazide, adipic acid, dihydrazide, and phthalic acid, dihydrazide. The aqueous urethane resin component used in the present invention has a urea bond nitrogen / nitrogen ratio related to the isocyanate reaction of 10/100 to 90/90.
In the range of / 100, two or more resin raw materials having a predetermined molecular weight and having a bisphenol skeleton and a carboxyl group in the resin skeleton may be used.

When a curing agent is not used in combination with the aqueous urethane resin, the crosslinking is insufficient and the corrosion resistance and the solvent resistance are inferior. Therefore, the curing agent is added in the present invention. As the curing agent, an epoxy compound, an oxazoline compound, an aziridine compound, an isocyanate compound, or the like can be used.
However, in order to obtain better corrosion resistance and solvent resistance, it is more preferable to use a water-dispersible or water-soluble epoxy resin or an isocyanate compound as a curing agent. Other curing agents often have a component such as acrylic or ester as a skeleton, and since the obtained film properties are affected by the components, the corrosion resistance and the coating adhesion may be reduced, which is not preferable. For example, when an epoxy resin is used as a curing agent, a cross-linking reaction becomes easy because the terminal epoxy group is rich in reactivity. When an isocyanate compound is used, the terminal isocyanate group reacts to increase the crosslink density in the molecule, and as a result, it is considered that tensile strength, solvent resistance, heat resistance, and the like are improved. Among these curing agents, an epoxy resin having a bisphenol skeleton is particularly suitable.

The compounding amount of the curing agent is preferably such that the ratio of the functional group in the curing agent to the carboxyl group contained in the skeleton of the aqueous urethane resin is 0.10 to 1.00. More preferably, it is 0.30 to 1.00. If this ratio is less than 0.10, the effect of compounding the curing agent is poor, and
If the amount exceeds the above range, the properties of the resin of the present invention cannot be sufficiently exhibited, and a crosslinking agent that has not reacted with the aqueous urethane resin remains to act as a plasticizer, so that corrosion resistance and solvent resistance are poor. descend. It is preferable that the solid content% by weight based on the total solid content weight of the curing agent is 30% or less. If the amount is more than 30%, the original performance of the water-based urethane resin cannot be brought out, and the performance such as corrosion resistance and coating adhesion deteriorates. In addition, since the sliding surface becomes 100 ° C. or more during strong working such as drawing or ironing as represented by press molding, it is possible to use a coating having a Tg in the range of 40 to 150 ° C. after crosslinking. preferable. If the Tg of the crosslinked film is less than 40 ° C., the tensile strength at high speed sliding, that is, at high temperature, is insufficient, so that the film is peeled off and the scratch resistance is reduced. On the other hand, if the Tg of the film after crosslinking is 150 ° C. or higher, the film becomes too hard to follow the elongation due to the plastic deformation of the material, and the film is damaged, and the corrosion resistance and the coating adhesion are reduced.

In the water-based coating composition of the present invention, the solid content weight% of (a) + (b) based on the total solid content (e).
Is preferably 50 to 95%. More preferably 5
5 to 75%. If it is less than 50%, the desired corrosion resistance cannot be obtained because the binder effect is insufficient. Also, 95
%, The desired corrosion resistance and scratch resistance cannot be obtained.

Next, the water-based metal surface treatment composition of the present invention contains silica (SiO ₂ ) in an amount of 3 to 40% based on the total solid content by weight to improve corrosion resistance. More preferably, it is 10 to 30%. If the silica solid content% by weight relative to the total solid content is less than 3%, the effect of improving the corrosion resistance is small, and if the content exceeds 40%, the binder effect of the resin is reduced and the corrosion resistance is reduced. Further, the particle size of silica is suitably 3 to 30 nm. If the average particle size is less than 3 nm or exceeds 30 nm, the intended corrosion resistance and coating adhesion cannot be obtained. The type of silica includes liquid-phase colloidal silica and gas-phase silica, but is not particularly limited in the present invention.

In general, when a lubricating additive is added to a metal surface treatment composition, the lubricating performance is improved. However, a lubricant such as graphite or molybdenum disulfide, which has been conventionally used as a lubricating component, is used to protect the environment and shorten the process. However, it is not possible to solve problems such as omission of the degreasing step after molding due to the formation. For this reason, in the present invention, the lubricating component preferably contains 2 to 30% by weight based on the total solid weight (e) of the water-based coating composition. More preferably, it is 10 to 25% by weight. The polyolefin wax has a saponification value of 0.
Or those having 30 or less and a branched structure are preferred. If the compounding amount of the polyolefin wax is less than 2% by weight, the effect of improving the formability is small, and if the amount exceeds 30% by weight, the wax is scattered around the press device and its periphery during the forming process, which is not preferable in terms of working environment and corrosion resistance. Also decrease. If the saponification value of the wax exceeds 30, the polarity is large and it is easily compatible with the resin, and it is difficult for the wax to be present on the resin surface at the time of film formation. Therefore, it is not appropriate when a high processing performance level is required. I can't say. More preferred are waxes having a saponification value of 0 and having no ester bonds having a lower compatibility with the resin. The average particle size of the wax is
0.1 to 7.0 μm is preferred. Average particle size is 0.1μm
If it is less than 30, workability is insufficient. If it exceeds 7.0 μm, the distribution of solidified wax is not uniform, which is not preferable. The melting point of the wax is 110
~ 160 ° C is preferred. When the temperature of the plate surface reaches 100 ° C. or higher during press molding, sufficient lubricity cannot be obtained if the melting point of the wax is less than 110 ° C. Conversely, if the melting point of the wax exceeds 160 ° C., The lubricating property of is not exhibited. Wax particles having a shape of a sphere or a true sphere are more preferable in order to obtain a high degree of workability.

In order to obtain a uniform film on the surface to be coated, the surface treatment composition of the present invention contains a surfactant or a thickener called a wettability improver, and a conductive agent for improving weldability. And a coloring material for improving the design.

Examples of the material to which the aqueous metal surface treatment composition of the present invention is applied include a cold-rolled steel sheet, a galvanized steel sheet or a stainless steel sheet. Further, it is preferable to perform a base treatment in order to improve corrosion resistance. A known chromate treatment or phosphate treatment is appropriate as the base treatment. The surface treatment composition is coated and dried on these base coats to form a coat of 0.3 to 5.0 g / m ² in consideration of performance such as scratch resistance, corrosion resistance, and solvent resistance. Is preferred. Examples of the coating method include a roll coater method, a dipping method, and an electrostatic coating method, but are not particularly limited in the present invention.

[0022]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples of the present invention and Comparative Examples. 1. Preparation of test pieces (1-1) Test materials The following commercially available materials were used as test materials. Double-sided electro-galvanized steel sheet (EG): Sheet thickness = 0.8 mm Weight per unit area = 20/20 (g / m ² ) Cold rolled steel sheet (SPCC): SPCC material, sheet thickness = 0.8 mm (1-2) Degreasing treatment The test material was a fine silicate alkaline degreasing agent, Fine Cleaner 4336 (trademark: manufactured by Nippon Parkerizing Co., Ltd.).
Degreased. (Concentration = 20 g / l, temperature = 60 ° C.,
(2-minute spray) (1-3-1) Base chromate treatment Chromate film formation of EG material is performed by Zinchrome 3367
(Trademark: manufactured by Nippon Parkerizing Co., Ltd.), spray treatment (bath temperature = 50 ° C, time = 10 seconds), and after washing with water 2
10 at an ambient temperature of 20 ° C (plate temperature reaching steel plate = 100 ° C)
Dried for seconds. The chromium deposition amount is 50 mg / m ² . (1-3-2) Base zinc phosphate treatment Zinc phosphate film formation is performed by Palbond L3020 (trademark:
Immersion treatment (bath temperature = manufactured by Nippon Parkerizing Co., Ltd.)
45 ° C., time = 2 minutes), washed with water and air-dried. The coating weight is 2.0 g / m ² . (1-4) Application of water-based metal surface treatment composition The water-based metal surface treatment composition shown in Table 2 was applied by a per coater, and the atmosphere temperature of 320 ° C (steel plate temperature = 160)
C) for 15 seconds. (Target adhesion amount = 1.0 g / m
² )

2. Painted plate performance test (2-1) Corrosion resistance A salt spray test according to JIS-Z2731 was performed for 400 hours, and the occurrence of white rust was observed. [Evaluation Criteria] ◎ = Rust generation is less than 3% of the entire area ○ = Rust generation is 3% or more and less than 10% of the total area △ = Rust generation is 10% or more and less than 30% of the entire area × = Rust occurrence is the whole area 30% or more of

(2-2) Corrosion resistance after processing Using a blank plate having a diameter of 100 mmφ, punch diameter =
50mmφ, wrinkle pressure 1Ton, deep drawing speed 30m
A high-speed cylindrical deep drawing test was performed under the conditions of / min. The aperture ratio at this time is 2.00. [Evaluation Criteria] ＝= Rust generation is less than 3% of the entire area ○ = Rust generation is 3% or more and less than 10% of the total area △ = Rust generation is 10% or more of the total area and no performance deterioration × = Rust generation is all Performance degradation occurs in 10% or more of the area

(2-3) High-speed scratch resistance Using a blank plate with a diameter of 115 mmφ, punch diameter =
50mmφ, die diameter 52mmφ, wrinkle pressure 1To
n, a high-speed cylindrical deep drawing test was performed under the conditions of a deep drawing speed of 30 m / min. The aperture ratio at this time is 2.30. [Evaluation Criteria] ＝= drawing-out to 2.40, good appearance 外 観: drawing-out to 2.40, poor appearance △ = drawing-out to 2.35 × = drawing-ratio = 2. Stopped down to 30

(2-4) Low-Temperature Scratch Resistance The test plate was cut into a width of 30 mm, the tip radius was 0.5 mm, the molding height was 4 mm, the crimping load was 0.5 Ton, and the drawing speed was 2
A draw bead test was performed at 40 mm / min, and the appearance was evaluated. [Evaluation Criteria] ◎ = No film damage ○ = The film damaged part is less than 5% of the whole sliding part △ = The film damaged part is 5% or more, 20% of the whole sliding part
Less than × = Damaged part of film is 20% or more of the entire sliding part

(2-5) Coating adhesion Melamine alkyd-based paint (trademark: Aramic # 100)
0, manufactured by Kansai Paint Co., Ltd.) and baked at 125 ° C. for 20 minutes, immersed in boiling water for 2 hours after 24 hours, and further baked for 24 hours.
Evaluation was performed after hours. Paint adhesion evaluation method is JIS-K
Each test of drawing, Goban-Erichsen, and impact was performed according to 5400, and the overall evaluation was made. [Evaluation Criteria] ＝= Coated area, 0% ○ = Coated area, 0-1% △ = Coated area, 1-10% × = Coated area, 10% or more

3. Test Results Table 1 shows a list of components of the aqueous metal surface treatment composition, and Table 2 shows a list of levels of the aqueous metal surface treatment composition. Examples and comparative examples will be described.

In Examples 1 to 10 in Table 3, the zinc-plated steel sheet was subjected to a chromate treatment and the cold-rolled steel sheet was subjected to a phosphate treatment, and then subjected to the aqueous metal surface treatment composition of the present invention (Table 2). N
o. 1) to 9) are applied and dried to form a film. Each of the corrosion resistance, the corrosion resistance of the processed portion, the scratch resistance, and the adhesion of the coating is good. On the other hand, No. 2 of Table-2 different from the present invention. In Comparative Examples 11 to 22 using the aqueous metal surface treatment compositions of 10 to 20, the corrosion resistance, the corrosion resistance of the processed portion, the scratch resistance, and the coating adhesion were inferior.

[0030]

By applying the aqueous metal surface treating composition of the present invention to the surface of a galvanized steel sheet or the like, a film having excellent scratch resistance during strong working and excellent coating adhesion can be obtained.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 22/07 C23C 22/07 22/24 22/24 22/83 22/83 28/00 28/00 C // C10N 20:04 20:06 40:20 (72) Inventor Yujiro Miyauchi 1 Kimitsu, Kimitsu-shi, Chiba Inside Nippon Steel Corporation Kimitsu Works (72) Inventor Atsushi Morishita 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Corporation Kimitsu Works

Claims (6)

[Claims] 1. A resin having a bisphenol skeleton and a carboxyl group in a resin skeleton and having an average molecular weight of 300
0 or more aqueous urethane resins, wherein the nitrogen content involved in the reaction of isocyanate during the synthesis of the resin is in the range of 2 to 13% by weight, and the urea bond in the nitrogen element involved in the reaction of the isocyanate during the synthesis of the resin. An aqueous urethane resin in which the nitrogen involved in the urea bond nitrogen / isocyanate reaction, which is the ratio of the nitrogen element according to the present invention, is in the range of 10/100 to 90/100, (b) a curing agent, and (c) silica;
(D) a polyolefin wax, and (a) + (b) solid content weight% of the total solid content weight (e)
Is 50 to 95%, and the equivalent ratio of the functional group in (b) to the equivalent of the carboxyl group contained in the skeleton of (a) is 0.1%.
0 to 1.00, 3 to 40% by weight of the solid content of (c) with respect to (e), and 2 to 30% by weight of the solid content of (d) with respect to (e). An aqueous metal surface treatment composition for forming a lubricating film with excellent scratch resistance. 2. The aqueous urethane resin has a nitrogen content of 5%.
The aqueous metal surface treatment composition according to claim 1, which is in a range of from 10 to 10% by weight. 3. The aqueous metal surface treatment composition according to claim 1, wherein the curing agent has at least one functional group selected from an epoxy group and an isocyanate group. 4. The aqueous metal surface treatment composition according to claim 1, wherein the amount of the carboxyl group in the aqueous urethane resin is 10 to 50 in terms of an acid value per solid content of the resin. 5. The polyolefin waxing value is 30.
2. The method according to claim 1, which is less than or equal to 0 and has a branched structure.
2. The aqueous metal surface treatment composition according to item 1. 6. The aqueous metal surface treatment composition according to claim 1, wherein the polyolefin wax has an average particle size in a range of 0.1 to 7.0 μm.